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ICC: Disentangling deactivation pathways in DNA bases and model systems using time-resolved photoelectron spectroscopy and three pulse techniques

ICC：使用时间分辨光电子能谱和三脉冲技术解开 DNA 碱基和模型系统中的失活途径

基本信息

批准号：
EP/H003401/1
负责人：
Vasilios Stavros
金额：
$ 28.78万
依托单位：
University of Warwick
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2010
资助国家：
英国
起止时间：
2010 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FH003401%2F1
关键词：
ICC Disentangling deactivation pathways DNA

项目摘要

While there has been a large flurry of experiments aimed at studying the photoresistive properties of biomolecules, recent progress in this field has been hampered by the growing complexity of the results observed, coupled to the increasing computational demands on theoretical simulations. Femtosecond (fs) time-resolved photoelectron spectroscopy (TRPES) provides unique capabilities for studying photoinduced processes and has successfully been applied to small polyatomic molecules. Photoelectron spectra are obtained via a two-step excitation-ionization scheme as the delay between the pump and probe pulses is scanned. The two-dimensional data obtained provides two-fold information on the evolution of the molecular system: lifetimes of the electronically excited states participating in the relaxation and decay associated photoelectron spectra for their spectroscopic identification. In the endeavour of applying this technique to molecules of increasing size and complexity such as biomolecules the following challenges become apparent: (1) Relaxation processes are complex due to the many degrees of freedom and an increasing number of low-lying states. (2) Processes that occur on similar, ultrafast time-scales and exhibit spectrally overlapping features are almost impossible to disentangle. The experiments by Ullrich/Stavros make use of two complimentary spectroscopic techniques at a high level of synergy that will allow wavelength-dependency studies with unambiguous identification of relaxation pathways. The expected outcome of this project is two-fold: (1) a detailed molecular level understanding of the photophysics of these molecules including competing pathways, onsets of deactivation channels, and the effect of structural modifications on the dynamics, (2) critical information for the design of three pulse TRPES experiments, such as expected signal levels and the feasibility of using inherently broadband fs pulses for excitation of specific reaction coordinates and narrow spectral lines. While this proposal focuses on experiments, ab initio computational studies will also tremendously benefit from the level of spectroscopic detail obtained in this stepwise approach. As most of the equipment is already in place at the respective institutes, all experiments will be performed by local and visiting students during extended stays in the PIs' laboratories and their collaboration will continue throughout data analysis and publication of their results. Both PIs have been integrating undergraduate and minority students in their research and this project will be no exception. Beyond the scientific aspect of this collaboration students will benefit from the exposure to a different academic environment and foreign culture. The project also seeks to exchange the PIs' experiences in outreach activities with the intention of implementing similar activities at their home institutions. For example, a former UK teacher (now outreach coordinator at Warwick) will participate in the Georgia Internship for Teachers program that places high school teachers into a research environment and aims at integrating their experiences into a lesson plan. In exchange UGA Physics will learn about Warwick's chemistry road shows for high schools and their E-learning approaches to publicize research to audiences in the wider community.

虽然已经有大量的实验旨在研究生物分子的光阻特性，但由于观察到的结果越来越复杂，加上对理论模拟的计算需求越来越大，这一领域的最新进展受到阻碍。飞秒（fs）时间分辨光电子能谱（TRPES）为研究光诱导过程提供了独特的能力，并已成功地应用于小的多原子分子。通过两步激发-电离方案获得光电子谱，扫描泵浦和探测脉冲之间的延迟。所获得的二维数据提供了关于分子系统演化的双重信息：参与弛豫和衰变相关光电子谱的电子激发态的寿命，用于其光谱鉴定。在将这种技术应用于尺寸和复杂性不断增加的分子（例如生物分子）的努力中，以下挑战变得明显：（1）由于许多自由度和越来越多的低位状态，弛豫过程是复杂的。(2)发生在相似的超快时间尺度上并表现出光谱重叠特征的过程几乎不可能解开。Ullrich/Stavros的实验在高水平的协同作用下使用了两种互补的光谱技术，这将允许波长依赖性研究，并明确识别弛豫途径。该项目的预期成果有两个方面：（1）对这些分子的生物物理学的详细分子水平理解，包括竞争途径、失活通道的起始和结构修饰对动力学的影响，（2）用于设计三个脉冲TRPES实验的关键信息，例如预期的信号电平和使用固有宽带FS脉冲来激发特定反应坐标和窄光谱线的可行性。虽然这个建议侧重于实验，从头计算研究也将极大地受益于这种逐步方法中获得的光谱细节的水平。由于大部分许褚已在有关研究所备妥，所有实验将由本地及访港学生在研究所的实验室逗留期间进行，而他们的合作将在数据分析及公布结果的整个过程中继续。这两个PI一直在整合本科生和少数民族学生在他们的研究，这个项目也不例外。除了这种合作的科学方面，学生将受益于接触到不同的学术环境和外国文化。该项目还寻求交流方案执行机构在外联活动方面的经验，以便在其本国机构开展类似活动。例如，一名前英国教师（现在是沃里克的外联协调员）将参加格鲁吉亚教师实习计划，该计划将高中教师置于研究环境中，旨在将他们的经验融入课程计划。作为交换，UGA物理学将了解沃里克的高中化学路演及其电子学习方法，以向更广泛的社区观众宣传研究。

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Manipulating dynamics with chemical structure: probing vibrationally-enhanced tunnelling in photoexcited catechol.

DOI：
10.1039/c3cp51108a
发表时间：
2013-04
期刊：
Physical chemistry chemical physics : PCCP
影响因子：
0
作者：
A. Chatterley;J. D. Young;D. Townsend;Justyna M. Żurek;M. Paterson;G. Roberts;V. Stavros
通讯作者：
A. Chatterley;J. D. Young;D. Townsend;Justyna M. Żurek;M. Paterson;G. Roberts;V. Stavros

Unraveling ultrafast dynamics in photoexcited aniline.